Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 15: Poster session I

MM 15.27: Poster

Montag, 7. März 2016, 18:00–20:00, Poster B3

Wurtzite to rocksalt phase transitions in binary compounds — •Ning Wang, Thomas Hammerschmidt, and Ralf Drautz — ICAMS, Ruhr-Universität Bochum, Bochum, Germany

A pressure-induced wurtzite-to-rocksalt phase transition is observed in many binary compound semiconductors, such as CdSe, GaN and w-SiC. We analyzed this transition with the generalized solid-solid nudged elastic band method and determined the enthalpy landscape with first-principles calculations. Our results show that at both lower pressure and higher pressure, CdSe, GaN, and w-SiC prefer the tetragonal transition path to the hexagonal path. Furthermore, at lower pressure, the tetragonal-sliding and tetragonal-compression paths have almost the same transition barrier due to a similar intermediate tetragonal structure. At higher pressure, this metastable structure cannot be stabilized and the tetragonal-sliding path becomes energetically more favorable. We furthermore test the performance of two force fields for CdSe, and find that neither of them is able to describe the enthalpy landscape with good accuracy.